Cellular communication devices use network radio access technologies to communicate wirelessly with geographically distributed cellular base stations. Long-Term Evolution (LTE) is an example of a widely implemented radio access technology that is used in 4th Generation (4G) communication systems. New Radio (NR) is a newer radio access technology that is used in 5th Generation (5G) communication systems. Standards for LTE and NR radio access technologies have been developed by the 3rd Generation Partnership Project (3GPP) for use by wireless communication carriers.
A communication protocol defined by the 3GPP, referred to as EN-DC (E-UTRAN/New Radio-Dual Connectivity) enables the simultaneous use of LTE and NR radio access technologies for communications between a mobile device and a cellular communication network. EN-DC may also be referred to as LTE/NR dual connectivity. EN-DC is described by 3GPP Technical Specification (TS) 37.340.